1. Field of the Invention
The present invention relates to a contact image sensor unit and an image reading apparatus using the contact image sensor unit.
2. Description of the Related Art
In an image sensor unit where a light source is arranged in proximity to an end face in a longitudinal direction (main scanning direction) of a light guide, leakage light is emitted from a gap between the light source and the light guide. Accordingly, illumination distribution cannot be maintained uniform in the main scanning direction.
Thus, an image sensor described in Patent Document 1 has been proposed by this applicant.
Patent Document 1
International Publication Pamphlet No. WO2008/013234
The image sensor described in Patent Document 1 has a configuration in which a part of a light guide cover is extended and thereby the light guide end and a light-emitting element are covered with the part. Thus, an image sensor without using the light guide cover has a problem necessitating an additional part and increasing cost.
Further, the image sensor without using the light guide cover has a configuration in which the light guide end is covered with the light guide cover. Accordingly, it is required to attach the light guide by sliding, in assembly. There is a possibility of danger of causing scratches and the like on the light guide. In addition, there is a possibility of danger of expansion of the light guide owing to variation in ambient temperature and/or causing scratches and the like during contraction.